Title: High-Quality Tremie Concretes for Underwater Repairs

Author(s): Kamal H. Khayat, Ben C. Gerwick, Jr. and Weston T. Hester

Publication: Symposium Paper

Volume: 122

Issue:

Appears on pages(s): 125-138

Keywords: adhesion; admixtures; air-detraining agents; blast furnace slag; bonding; compressive strength; repairs; silica fume; tremie concrete; fly ash; underwater structures; water-reducing agents; Materials Research

DOI: 10.14359/2484

Date: 6/1/1990

Abstract:
The underwater placement of small concrete volumes for repair operations necessitates that the fresh concrete be highly resistant to water erosion and segregation, as well as self-compacting and self-leveling. The hardened concrete must develop high wear resistance and excellent adhesion to underlying surfaces and reinforcing steel. Four potential repair concretes and one conventional tremie mixture were cast underwater in small and relatively shallow depressions using tremie pipes. Research findings indicate that an anti-washout admixture should be used to minimize the risks of water dilution and segregation and to enhance the spreadability and leveling of underwater-cast concrete. Proven concrete mixtures recommended in this research can produce relatively flat repair surfaces with in-place compressive strength in excess of 8000 psi (55.2 MPa) and relative density close to 100 percent of similar values for concrete cast and consolidated above water. Bond strength close to 400 psi (2.8 MPa) can develop between underwater-cast concrete and neighboring concrete repair surfaces.